Southwest Trip '99

Hoodoos

Most Hoodoos (capped rock structures -- the upper layer contains more lime
and is more resistant to erosion than the soft red sandstone beneath it,
and so protects the column somewhat from erosion) are farther south,
in the Needles district of Canyonlands, but there were a few in
Island in the Sky. This was a nice collection.

Mesa Arch

Mesa Arch is probably the best arch in Island in the Sky (though not as good
as those in Arches National Park).
A famous photograph is to shoot Washerwoman Arch looking through Mesa Arch.
This can be spectacular if the lighting is right -- ideally, you want a beam
of sunlight coming through the clouds to illuminate Washerwoman and make
her stand out against the other rock features nearby.

Not having the patience for this, I snapped a picture in the light available
to me at the time (left). At right, you can see how precariously one side
of Mesa Arch is held, and the steepness of the drop behind it

The Needles District of Canyonlands

Our first stop in the Needles district was a roadside stop showing some
impressively layered hoodoo pillars, and walls of tafoni -- sandstone
sculpted by wind erosion into fanciful patterns.

We took a short hike on the "Pothole Trail", a slickrock surface where
life begins in potholes, either as a plant colony beginning as
cryptobiotic soil (the lumpy black stuff in the foreground of the
right picture) or as tiny dehydrated fairy shrimp (left) which come to life
during the rainy season, grow, mate, lay their eggs and die before
the coming of the next dry season.

The Pothole Trail also had some wonderful rock formations on it,
like this little elephant.

But we didn't expect to find Mt Rushmore in Southern Utah!

Newspaper Rock, perhaps the most famous of all Indian petroglyph sites,
sits beside the road leading in to the Needles.
Indians of many tribes spanning perhaps thousands of years carved
pictures into the desert varnish covering this rock.
The carvings range from abstract spirals and suns, and squiggles
which might be snakes or might simply be abstractions, through animals
(lots of flying squirrels and bighorn sheep, turtles, herds of reindeer)
to people -- normal people, people with horns or other animal features,
and people riding horses, to actual writing obviously added by
modern visitors. (The fine for writing on the wall is $200.)
The signboard beside the wall is refreshingly honest: basically,
that there are lots of theories but no one really knows what any of it means.

Wilson Arch

Wilson Arch is one of the more impressive arches in Utah -- and part of
what's impressive about it is that it's just sitting by highway 191
approaching Moab from the south.
No park, no entrance fee, no rules, just look, explore, enjoy.

You can hike right up to it. See Dave standing at the base on the right?

Left, a huge flake clinging to the wall nearby. I wonder how long it
will continue to cling?
Right, a close-up of the base of Wilson Arch (and lands beyond).

The Black Canyon of the Gunnison

The Black Canyon of the Gunnison is one of the narrowest and deepest
canyons in the United States (and perhaps the world). When the uplift
of the Rocky Mountains began, the Gunnison river was already well
entrenched into a canyon in Mesozoic sandstone (the same sort of
red-rock sandstone as you see in most of the canyons in Utah).
But below the soft sandstone lay hard Precambrian gneisses and granites,
and once the Gunnison had cut through the sandstone, it had nowhere
else to turn, so it continued cutting a canyon through the hard black rock.
Later, as the uplift continued, almost all of the sandstone wore away
(there's one place where you can see a small dome of red Cretaceous
Entrada sandstone -- the same rock that makes the arches in Arches
National Park, at the very top of the Mesozoic sequence you find
on the Colorado plateau) and now only the Precambrian is left.

The rock of the Black Canyon is very hard, very black, and very steep.
The Gunnison, at the bottom of the chasm, was bright green in this late
fall season.

Notice, particularly in the picture on the left, the difference between
the slopes of the two sides of the canyon. This photo was taken facing
eastward; the south wall of the canyon stays colder in winter, and
develops more ice, which then causes fractures in the wall, leading to
greater erosion in that wall and a more gradual slope. The better-lit
north wall stays freer of ice and holds its steep slope.

Pegmatite dikes make huge pink streamers through the otherwise mostly black
walls of the canyon. Up close, the pegmatite looks almost like rose quartz.
There are also intrusions of granite and mica schists. The "Painted Wall"
(left) is the best display of patterns in the north wall of the canyon.